This invention pertains to rubber cement formulations. More particularly, this invention pertains to adhesives containing a rubber elastomer, a tackifier, and an organic solvent that is not a hazardous air pollutant (HAP).
The current, commercial adhesive products contain large amounts of hazardous air pollutants (HAP""s) solvents, including methyl ethyl ketone (MEK), toluene, xylene, tetrachloroethylene, perchloroethylene (PERC) and methyl isobutyl ketone (MIBK). Hazardous air pollutants are those substances that may cause immediate or long-term adverse effects on human health such as cancer and are listed on the United States Environmental Protection Agency""s list of HAPs. The adhesive industry has been desirous of fast drying new non-HAP containing rubber cement formulations with excellent adhesion to cellular insulation both nitrile and polyethylene.
Thus, there is a need for a new adhesive that meets these demands.
Our invention is a non-HAP containing rubber cement that affords excellent adhesion, safety, application speed, and ultimately good overall performance and cost reduction. This invention relates to low viscosity HAP-free contact adhesive compositions that have good adhesion to a variety of substrates. More particularly this invention relates to the use, for example, of polychloroprene elastomers, nitrile elastomers, and styrene-butadiene elastomers in combination with phenolic tackifiers in adhesive formulations to achieve HAP-free, high strength, commercial adhesive formulations. For instance, these rubber cements are used for the bonding of cellular insulation to itself, tile to concrete, metal to metal, canvas-to-canvas, and rubber-to-rubber, as well as combinations of these adherends. The rubber cements of this invention can achieve environmental compliance with the United States Clean Air Amendment, 1990, Sect. 112, HAPs and United States President Clinton""s Executive Order 12856. The non-HAP containing rubber cements of this invention dry quickly yet provide equal or better adhesion than the historic HAP containing rubber cements when bonding cellular insulation, tile, canvas, aluminum, polychloroprene and polyvinyl chloride calendered fabrics.
Rubber cements have used for bonding a wide variety of adherends since the 1960""s. However, dangerous solvents such as methyl ethyl ketone, xylene, toluene, dichlorobenzene, have been historically used in these products. The new adhesive of this invention will provide strong durable bonds for the tile, cellular insulation, and other applications and provide greater personal safety for the employees. The new rubber cements of this invention provide faster and easier application, in addition to quick application time that will reduce maintenance costs. Costs associated with environmentally unacceptable adhesive ingredients can be eliminated. Also, if desired subsequent removal of the adhesive can be accomplished by an environmentally acceptable solvent, eliminating HAP solvent use at all levels.
In one respect, this invention is a rubber cement composition, comprising a non-HAP aprotic, non-aromatic solvent; a tackifier; and an elastomer. This composition may also include magnesium oxide and/or zinc oxide. It should be understood that this composition is formulated from these components, and components such as the magnesium oxide may react with water and/or the elastomer, for instance, thereby reducing the amount present. As such, it should be understood that the composition may alternatively be referred to as having been formulated from components which comprise a non-HAP aprotic, non-aromatic solvent, a tackifier, and an elastomer, optionally including a metal oxide such as magnesium oxide and zinc oxide, and optionally including a small amount of water if magnesium oxide were included.
In another respect, this invention is a process for manufacturing a rubber cement composition, comprising: dissolving a tackifier and an elastomer in an aprotic non-aromatic non-HAP organic solvent.
In another respect, this invention is a process for adhering a first substrate to a second substrate, comprising: applying a rubber cement composition to a surface of the first substrate, applying the rubber cement composition to a surface of the second substrate, and pressing together the surfaces having the rubber cement composition applied thereon of the first and second substrates to thereby adhere the first and second substrates to each other.